o365 f1 plan pop3 email client

Using POP3 and Windows Live Mail is a really bad idea when you move to the cloud.

I might just tolerate the suggestion for an on-premises deployment when everyone is behind a corporate firewall, but when you move to Office 365 those F1 users are going to be on the internet and you're asking them to use an antique mail protocol from the 1980s and an antique mail client that's designed for consumer use. This is a recipe for hacker attacks.

As you're paying for OWA, you should use OWA and take advantage of the more modern protocols and the anti-malware capabilities built into the client. OWA supports offline use too. You can configure mailbox retention policies and low mailbox quotas to keep user mailboxes under control.

Seriously, it's time to move into the 21st century.